1. Field of the Invention
The present invention relates to an integral butt-joint to connect two pipes which, by realizing between both pipes two distinct metal tight seals with interference engagement activated by the same operation of screwing down of said pipes into each other, makes it possible a tight seal to be accomplished which is effective and reliable even under extremely harsh operating conditions, i.e., high differential pressures and temperatures.
2. Discussion of Background
From the prior art, different types of integral joints, i.e., joints obtained by simply screwing down the pipes to be connected, and therefore with no use of auxiliary organs (sleeves) in order to achieve the mechanical continuity, and the tight seal between the same pipes.
Furthermore, some known types use an all-metal mechanical tight seal with interference between the end of the male pipe and the corresponding seat provided inside the female tube, in which corresponding conical (tapered) surfaces are purposely provided in order to secure the tightness of the joint.
Unfortunately, none of these solutions known from the prior art secures an effective tight seal behaviour when the operating conditions become extremely harsh with high differential pressures, temperatures and tensile/compressive stresses applied to the joint, such as are found in petroleum field, e.g., in well completion.
The purpose of the present invention precisely is of obviating the above drawbacks and therefore supplying an integral joint of two pipes capable of securing always the tightness of the joint under any operating conditions, and, thus, allows a safe and reliable transport of also corrosive liquids, to be accomplished.